Contents

Executive Summary

For this project, Group 12 decided to use a Weedeater brand leaf blower to dissect and analyze. The group came together with a specific interest in working with a small engine because a few of the members already had knowledge of its mechanics. Our main goal throughout the course of this semester was to dissect, document, analyze, and reassemble our product in a way that would help us understand how the product works, the reasons and methodology behind the design, and the overall impact in terms of GSEE requirements.

Our product works using a single cylinder, 2-Stroke, gas-powered engine. The engine used spark ignition, drawing its energy from a generator attached to the spark plug. The casing and all other components were pretty standard for a simple, residential style, leaf blower. During the course of the project we were able to compile information about the products systems and subsystems to generate a list of suggested design changes. These changes would better enhance and improve the product in a way that would implement a benefit to Global, Societal, Economic, and Environmental factors. The general design changes on a subsystem level were in response to the products handle, housing, choice of power, and exhaust. The suggestions to a change in design on a system level regarded the engine type, interface, external, implementation of a harness, and redesign of the combustion chamber.

These suggestions have all been thoroughly examined with the documentation achieved from the assignment gates during the group work timeline.

Gate 1

The first gate of the product was a general analysis of the development, usage, energy, complexity, material, and interaction profiles. We individually created profiles for each general description of the leaf blower. We documented the generic components and visual appearance and interface components as well as the ease of use and the methods for use. After combining the information into an overall product profile, our group came up with a method for keeping a timeline and schedule for meetings and future gates.

We used this original plan for a group schedule as the baseline for how our group would be able to begin this project. We then compared what would be more realistic in terms of our work and when it should be completed by. Also, the product profile provided us with an initial view on a low complexity of our product as a whole design system.

Gate 2

In the second gate of the project we systematically disassembled the leaf blower. We started with the outside casing and unscrewed and unbolted pieces as we went, documenting each piece carefully and what we took it apart with. After organizing the parts, we took pictures of each part and labeled each picture for the wiki page. We disassembled the product down to the piston and combustion chamber and every subsystem was able to be taken apart from the original product. We were also able to finalize our group work plan and management plans.

Because the product was held together with screws that most if not all households would have replacements for and tools to dismantle them, as well as the ease of taking apart the product, we came to the conclusion that this product was designed for the user to fix and maintenance. Each part was simple to take out and hypothetically replace, thus making it very user friendly in terms of the maintenance. In addition, the work management plan changes were more effective in controlling the quality of work and the meeting times that worked best for every group member.

Gate 3

The third gate was about determining what materials the parts were made out of and what method was used to create them. We also took every subsystem and documented them in terms of function, form, manufacturing methods, and complexity and then created a three-dimensional model of the systems. The documentation was mostly written individually and formed together to create an overall subsystem profile.

After we separated each piece of the product and determined the material makeup and origin by manufacturing process, we were able to categorize the subsystems in a way that described them more in depth. The documentation of earlier pictures was used to identify each part and subsystem. Using this information we also compiled a list of suggested revisions to the design at a system level that would benefit the product in terms of the GSEE factors.

Gate 4

The fourth gate was the reconstruction and reassembly of the product from the pieces that we disassembled and separated. Each step that was done was documented and judged based on the difficulty to reassemble. The documentation was already done in terms of individual parts and the reassembly was done with pictures as documentation of reassembly. We also summarized the mechanisms found within the system and the governing equations these mechanisms were built around and founded upon.

Reconstructing the product took the directions on how to disassemble the product that we developed earlier in the product timeline. After separating the mechanisms and describing them we were able to document both the mechanisms in depth and the products reassembly. Using this information we also compiled a list of suggested revisions to the design at a subsystem level that would benefit the product in terms of the GSEE factors.

Final Design Revisions

Design and attach a more silent muffler. Design and manufacture a small catalytic converter to add to the exhaust output. This would allow the user to use the leaf blower more often without bothering their neighbors. This is a societal factor as the use of these leaf blowers often create and abundance of noise and can easily irritate people close by but with this proposed design change this would no longer be an issues.

The addition of plastic loops on the product for the easy assembly and remove of a strap or harness would help with the distribution of the leaf blower’s weight and this would assist the user in handling and operating the product. this simple addition would increase the product audience have those whom many have found the leaf blower uncomfortable or too heavy to hold will now be able to user the product with more ease. This addition would be a societal factor as the product has become more diverse in the product audience.

Redesign the Combustion Chamber, Creating a smaller combustion chamber by decreasing the deck height of the cylinder head will lead to more compression and torque, resulting in more air output. This would most likely shorten the amount of time the product would need to be used in one session with can increase the life span of the product and would also decrease the duration of the loud noise produced by the engine. This is a economic factor as by increasing the life span of the device there will be less repairs needed and there less money needed to be spent to maintain the device.